Writer: Edith A. Chenault, (979) 845-2886, firstname.lastname@example.org
Contact: Dr. Deb Zoran, (979) 845-2351
COLLEGE STATION — Blame El Nino for one more thing — a higher than normal possibility that your dog or cat could get heartworms this summer. But, prevention is still the best medicine when it comes to heartworm disease, according to a veterinarian with Texas A&M University.
“Prevention is the key,” said Dr. Deb Zoran, a veterinarian specializing in small animal medicine. “It’s the safest, simplest thing you can do and there are so many products out there now.”
Basically, if there are mosquitos around — even in arid regions – – there is a chance that pets will get heartworms, she said.
“West Texas is a lot like Arizona and New Mexico. You will see heartworm in some of those areas and certainly in those areas where they have irrigation or any kind of water,” she said. “When I was in practice in Arizona, we had heartworm in the city. It’s where the water was, where people were either growing yards or gardens or watering of some sort.”
Heartworms are transmitted to pets through the bite of a mosquito. When taking a blood meal from an infected dog, the mosquito picks up the microfilaria or the baby heartworms. Within the mosquito, the microfilaria go through their life-cycle to the infective stage. At that point, the heartworms can be transmitted to the animal, Zoran said.
In dogs, the infective microfilaria go through a number of life- cycle stages, migrating through the animal’s tissues until they end up at the base of the right heart in the main pulmonary artery.
A dog may have heart worm disease for six months and the owner will not know about it. Symptoms of heartworm disease in dogs may be very subtle. The dog may be exercise-intolerant; they will not be able to run as long or work as hard. The dog may have developed a cough from the microfilaria living in the main pulmonary artery, which goes from the right heart up into the lungs. Dogs with severe heartworm disease may be coughing because they actually are having heart failure. The pet will eventually die unless treated.
Dogs are a natural host to heartworms, and contrary to popular belief, cats also can get heartworm disease, she said.
Veterinarians at Texas A&M recommend dogs be checked annually for heartworms. And both dogs and cats — especially in East and South Texas where mosquito populations are much greater — should be kept on heartworm preventative year-round, Zoran said.
There are two types of heartworm medicine available for dogs — the daily dosage and the monthly dosage. Zoran considers the monthly dosage more effective than the daily dosage; if a dog misses its medicine for a day or two while on the daily type, it could still contract heart worms.
Cats are known as a “barren host” — in other words, the life cycle of the heartworm cannot be completed in the cat. However, Zoran said, occasionally after cats are bitten by a mosquito with microfilaria, the worms will migrate to the base of the heart.
She explained she did not know what percentage of cats can get heartworm disease. “However, there are two things we do know,” she said. “First of all, when you do get a heartworm, you have a much smaller heart size than in a dog, So one or two worms will make a huge difference in a cat.
“Last but not least, our treatment drugs we use in dogs cannot be used in cats, at least not yet. They will actually kill a cat,” she said.
Diagnostic tests are not as effective in cats, she said, because they have to be able to detect only one or two worms.
There are heartworm preventatives for cats, and she recommends these for people in states along the Gulf Coast and the eastern half of Texas. “If you’re outside these regions, there is a lot of debate as to whether it is really necessary or not,” she said.
Treatment after the dog gets heartworms is not a good option, Zoran said, because the arsenic-based products used to treat heartworms are so dangerous. The heart worms literally die and start to break into pieces, she said. “There’s all kinds of possible problems that can happen as a result of that,” Zoran said.
The bits and pieces of worms could clog blood vessels and the products themselves may cause liver or kidney problems. Therefore, owners must keep their dog very quiet for about four weeks to allow all the worms to die and the body to reabsorb the dead worm tissue.